This invention relates to a solvent recovery system for use in drying articles at relatively low temperature, and is particularly applicable to dry cleaning of clothing and the like.
In the past, a dryer has been used to recover the solvent absorbed by clothes which have been cleaned to remove dirt. After being washed in solvent, the articles are placed in the dryer and hot air from a heater is blown onto the clothes to evaporate the absorbed solvent. Separation of the solvent from the clothing occurs and the evaporated solvent is subsequently cooled by a cooler for condensation and recovery of the solvent.
The hot air for the solvent evaporation is obtained from a separate boiler. A chilling unit or well water is used for cooling the air after passing through the dryer, and the heat from the exhaust is discharged into the atmosphere from the cooling tower or an air cooled condenser.
Consequently, there is a waste of discharged heat from the chilling unit and, furthermore, the overall construction is big and cumbersome and a boiler is required to be installed as a drying device for the purpose of solvent recovery. When boiler steam is used as a heat source, the temperature is near 100 degrees Celsius (near 212 degrees F.) and the temperature inside the tumbler is difficult to control. Sometimes the heating inside the tumbler exceeds the ignition point of the solvent and an environment is created in which the solvent ignites easily and a situation is produced in which there is danger of an explosion caused by the ignition of the solvent. Such earlier systems are expensive and the operating conditions for correct vaporization and condensation to take place are difficult to achieve. Further, such systems have the disadvantage of complexity due to the numerous adjustments required during the process of operation of the system.